The invention relates to an annular elastomeric seal-ring construction of the variety suited to establish a sealed interface between two relatively rotatable members, such as a shaft and the bore of a supporting body in which the shaft is journaled.
Of the various elastomeric seal constructions devised to establish a circumferentially continuous sealed running interface between two relatively rotatable members, the O-ring is most currently favored. It has a circular cross-section and is generally retained in a circumferential groove of rectangular section in one of the rotatively rotatable members; the circular section is stabilized in its retention between spaced parallel walls of the groove section, and the circular section is in circumferentially continuous resiliently stressed contact with the bottom of the groove, while also in resiliently stressed wiping contact with an opposed circumferentially continuous surface of the other member. For a shaft and its supporting journal, such a seal necessarily establishes but a line of sealing contact, wherein said line is in a single radial plane of the axis of relative rotation, thus limiting lubrication of the line of wiping contact. Further, such a seal tends to rotate locally about its section, becoming torsionally twisted and stressed in the course of axial assembly of a shaft to its journal.
The so-called quad-ring section has been devised for elastomeric seal rings, in an effort to stabilize the same against torsional twist, either in the course of assembly or otherwise. Such a ring establishes two axially spaced lines of circumferentially continuous contact at the wiping interface. However, each of these lines is in its own single radial plane of the rotational axis, thus limiting lubrication of both lines of wiping contact.
So-called lip seals are known in which a circumferentially continuous elastomeric lip is molded or otherwise bonded to the circumferential flange of a steel sleeve adapted for force-fit or other retention in a counterbore of the shaft-supporting member. The lip section provides resiliently cantilevered axial offset for the locus of seal contact with the shaft, in reference to the location of flange support, and the seal-contact region of the lip is characterized by a radial projection which axially undulates to sweep an axial range of shaft contact for each cycle of rotation. A circumferential spring is carried by the lip, behind its region of shaft contact, in order to establish desired resilient loading of the locus of shaft contact.